Sealing and Insulating a Newport News, VA Crawl Space

Challenge

This homeowner in Newport News called us out to inspect their crawl space for possible moisture issues and damage. We sent out one of our well-trained Home Performance Advisors to evaluate their crawl space and immediately noticed there were many areas of the crawl space that we're missing any sort of liner or vapor barrier. These exposed areas were allowing moisture to rise from the earth and affect the crawl space's relative humidity and environment.

Mold and mildew growth had already formed along many of the floor joists, which can occur on any organic materials so long as the relative humidity reaches over 60% during warmer temperatures. Musty odors and mold spores can then find their way up into the home and irritate those with allergies and asthma.

The excessive moisture was also being absorbed by the fiberglass insulation batts, causing it to fall out of place in chunks under the extra weight. Moisture was also finding its way through the foundation walls. Efflorescence was visible along the walls, suggesting that moisture had seeped through these porous cinderblocks, bringing along with it the inner salts and sediments to the surface, creating a chalky, powdery substance along the walls.

Open vents lining these walls were also allowing the outside air and moisture to freely enter the crawl space and affect the relative humidity and environment. Our advisor and the homeowner came to an agreement on our proposals, and we began the work to seal and insulate this damp and unprotected crawl space.

Solution

We first wanted to clear the crawl space of old materials, so we removed the old liner, the fiberglass insulation batts, and any building debris or trash. Then we applied an antimicrobial to any affected floor joists to remove mold growth. This application eliminates mold and mildew but it does not remove the staining left behind by growth.

Once the mold growth was eliminated, we installed a 20-mil CleanSpace vapor barrier over the dirt flooring of the crawl space. This heavy-duty liner gets wrapped around all piers, sealed with vinyl tape, and mechanically fastened to the foundation walls six to eight inches above outside grade. CleanSpace will help to protect the crawl space from moisture rising out of the earth and make it easier for us to seal off any outside influence.

We then focused our attention on the foundation walls, where moisture was not only seeping through the porous cinderblocks but also entering through the open vents lining the walls. We blocked off each vent by inserting a custom foam board piece into the inner side of each vent and sealing it with can foam. Then we used closed-cell spray foam to cover the foundation walls, which at an inch and half-thickness, will act as an air barrier and vapor retarder. A two-inch viewing strip was left on the upper perimeter of the foundation wall for termite inspectors.

Finally, we installed a SaniDry Sedona dehumidifier in the crawl space, along with a LittleGiant condensation pump. This highly efficient dehumidifier will help to circulate dry air around the crawl space while pulling in moisture and draining it via a condensation pump and hose line. This will help to regulate the relative humidity of the crawl space, and the homeowner is given a hygrometer to always monitor this and the temperature of the crawl space.

With these solutions set in place, the homeowners should experience a more comfortable and energy-efficient home. Outside air and moisture will find it more difficult to penetrate the crawl space's defenses, and annual service and maintenance calls are made to the homeowner to maintain this protection. If you are experiencing moisture issues of any kind in your crawl space, then give us a call at 757-566-8622. We'll help to keep the outside, outside!